Abstract: A method and system for determining a useful life of financial instruments, such as financial assets and liabilities. A dynamic calculation of a first retention rate is performed for each of several financial assets; a steady-state calculation of a second retention rate is performed for the financial assets; and the first and second retention rates are combined to determine a predicted useful life of the combined financial assets. Optionally, one of several variables affecting at least one of the retention rates is selected. A sensitivity of financial asset variables to other financial asset variables is determined. Scenarios are forecast, extrapolated from the retention rate. The financial assets may include deposits and/or financial instruments. Outliers in the financial assets may be checked, in one variation of the invention. Exogenous variables may be included in at least one of the calculations.